Call recording system



Dec. 13, 1949 M. POTTS 2,491,205

CALL RECORDING SYSTEM Filed Dec. 28, 1945 4 Sheets-Sheet 1 INVENTORLOUIS M. POTTS DECEASED '{MRTHA W.C. POTTS, EXECUTRIX BY J WM ATTORNEYL- M. POTTS CALL RECORDING SYSTEM Dec, 13, 1949 Filed Dec. 28, 1945 4Sheets-Sheet 4 LOUIS M. POTTS DECEASED MARTHA w.c.POT1's, axscu'rmxINVENTOR ATTORNEY Patented Dec. 13, 1949 Louis M. Potts, deceased, lateof .Evanston, IlL, by Martha W. C. Potts, exec'u'trix, Evanston, Ill.,ass'ignor .to Teletype Corporation, Chicago, 111., a corporation 'o'fDelawa re' Application December 28, 1945,.- SeriaLN 0. 637,650

13 Claims. 1

The present invention relates to telephone systems and more particularlyto call recording apparatus and circuits for use therein.

Apparatus and circuits have previously been devised for use in callrecording or recording a calling subscriber's number at a calledsubscribers station when the latter is absent and/or fails to answer thetelephone. However, such solutions utilize very complicated apparatusorder to achieve the desired results;

Accordingly, the main object of this invention is to provide simplifiedapparatus-and circuits .ior generating and recording 'a callingsubscriberfs number at an absent called subscribersstation.

A further object of the invention is to provide such apparatus andcircuits which will operate automatically after a predetermined numberof bell rings have gone unanswered.

Still another object or the invention isthe provision of a specialoperator's station to which may I be transmitted a message to be left atthe absent called subscribers station and which will be transmitted andrecorded thereat under the control of the leave word operator.

A still further object of the invention includes apparatus whereby thecalling subscriber s number will not be recorded at the absent calledsubscribers station until the former concludes his attempted call andreplaces his phone to a normal unoperated condition.

The features and advantages of the invention will become apparent fromthe following detailed description of specific embodiments thereof, whenread in conjunction with the accompanyingdrawings, in which:

Figs. 1, 2, and 3 illustrate a telephone system incorporating thereincall recording apparatus and circuits, and should be Viewed togetherfrom left to right, respectively;

Fig. 4 is a view similar to Fig. 1 but incorporating apparatus wherebythe call recording will not occur until the calling subscriber hasreplaced his station apparatus to an unopera'ted condition, and shouldbe viewed with Figs. 2 and 3, and

Fig. 5 shows a leave word operators-station.

The following description will only refer to so much of the telephonesystem asis necessary for a complete understanding of the invention. Thetelephone system utilizedis oi the: panel dialtype, is standard, and iswell known to those versed in the art.

Referring to Figs. 1 to 3,:inclusive, Fig. 1 shows a calling subscribersstation .A and lines H conncc'ted through a line finder' district l2to'an-oflice selector 13, which is-con-nected through an in-. comingselector circuit I4, Fig. 2; a final selector [5, Figs. 2 and '3, andover the lines ll to a called subscribers stationB. The line finder andselectors are of the panel type and may be similar to the constructionand operation of the switches disclosed in United States Patent1,123,696, issued to Craft .et al. on January 5, 1915.

In the following description an assumption will be made that the calling.subscribers station A has been dialled in accordance with the callnumbers of the called subscribers station B and that the .line finderdistrict 12, the ofiice selector it, the incoming selector circuit TMand the final selector 16 have operated in accordance will the usualpanel dial telephone circuit operation to connect the calling station Awith the called station B and condition a talking circuit which will beestablished by the subscriber at station B removing the receiver.

Such a connecting circuit may be traced over the lines H from thecalling subscribers station A to tip and ring connections 13 and I9,respectively. Further, the circuit may be traced from grounded batteryiI through the left-hand winding of a repeater coil 2-2, through theWinding of a relay '23 and over conductor 24 to the ring connection l9and thus to one-side-of line I]. The completed circuit may :be .furthertraced 'from the other side of line -I I, through the tip connectionl8,over a conductor 26, and through the lefthand winding of a repeater:coil 21 to ground at 2 8.

Further tracing of the circuit, through the line finder district :I 2may be made from the induced current in the right-hand winding of therepeater coil 21, through sequence switch cam 29 which will form aclosed path at this time, over aconductor 34 to a connector 32 in theofiice selector I3. The other half or side of the circuit may be tracedfrom the right-hand winding of repeater coil 2-2, over a :conductor 33,through thesequence switch cam 34 which forms a closed path at this timeand over conductor-3t toeonnector 31 in the oiiice selector 13; v

The upper half of the circuit tromconnector 32 in the "office selectort3 may be traced to the incoming selector circuit l4 over conductor 8,through sequence switch cam 39. which forms a closed. path at this time,through the left-hand winding of a repeater coil ill -lover a conductor42, through an armature 43 of arelay M which is in its unoperat-ed orleft-hand position, and through aeonductor cc and the left-hand windingof'a relay l! to grounded battery-48. The opposite side of the circuitmay be traced from the connector 31 in the ofilce selector, overconductor 49 to the incoming selector circuit M, through the sequenceswitch cam 59 which will be in position to form a closed path at thistime, over conductor 52, through the left-hand winding of a repeatercoil 53, over a conductor 54, over a conductor 56, and through theright-hand winding of the relay 4? to ground at 51.

The circuit from the incoming selector circuit It to the final selectorI6 will result through induced circuit occurring in the right-handwindings of the repeater coils H and 53. Such circuit may be traced fromground, through the right-hand winding of repeater coil 41, through asequence switch cam 58 which forms a closed path at this time, over aconductor 59, through an armature 61 of a relay 62 which is in itsunoperated condition at this time, and over a conductor 63 to aconnector 64 associated with the final selector circuit it. The oppositehalf or side of the circuit may be traced from grounded battery 66,through the right-hand winding of the repeater coil 53, over a conductor67, through the winding of a relay 68, through a sequence switch cam 69which will be closed at this time, over a conductor H, through anarmature 12 of the relay 62 which is in its downward or unoperatedcondition, and over a conductor 73 to a connector 14 associated with thefinal selector I6. The connectors 64 and 14 are connected by means ofthe lines I! to the called subscribers station B.

The circuit just described is conditioned only, and will be fullyestablished upon the called subscriber answering his phone. The relay 23at the line finder district l2 will be energized as the callingsubscriber at station A has his receiver removed, but the relay 88 inthe incoming selector l4 will not be energized as the receiver atstation B has not been removed.

Upon the conditioning of the circuit described above a machine ringingrelay 15 will be energized, in a manner well known in standard telephonepractice, to cause the bell to ring at the called subscribers station Bindicating a telephone call. The relay 15 remains energized until suchtime as the called subscriber answers his phone, at which timesuperposed direct current prevents further operation. As a result of theenergization of the relay ringing current is applied through analternating current relay 16 which has been added. Even though the relay15 remains energized the relay 16 will be caused to operate onlyintermittently, as the alternating current is supplied at intervals,interspaced by periods of rest. In the event that the subscriber atstation B removes his receiver, causing relay 15 to become de-energized,as previously mentioned, the relay 16 will no longer receive alternatingcurrent and will remain tie-energized.

However, in the event that no one is present at the called subscribersstation B or for some other reason the receiver is not removed from thehook, the telephone thereat would continue to ring until such time as thcalling subscriber A discontinued the call and the telephone circuitselecting apparatus automatically broke the circult. In the presentinvention means are provided whereby in the event that there is no response at the called subscribers station 13 after a predetermined numberof bell rings, an apparatus will be operated to record the callingsubscribers number at the called subscribers station. Such apparatuswill now be described.

With reference to Fig. 1, a signal generating apparatus 11 is providedwhich would be located at the central telephone station but which willgenerate numbers indicative of the subscriber's stations associated withsuch central station. The signal generator 11 includes a pair ofdistributor rings such as the segmented ring 18 and the solid ring 19which are traversed by the brushes 8|. The segmented ring 18 issegmented in such a manner as to generate signals indicative of thestation call letters of the calling station; that is, the identifyingletters only. If in the following description it is assumed that thecalling subscribers number is BUC 6200 the ring 18 would be segmented inaccordance with the letters BUC.

It might be well to point out at this time that the telegraph signalswhich are transmitted through the switching equipment are modulatedalternating current of a suitable audible frequency. These signals areof this character so that they can be transmitted through condenserswhen required and are adapted to pass through the various link circuitscommonly used in telephone service. The signals are later converted todirect current signals, as will be described, suitable for operating amonopulse printer of the type and in the manner disclosed and describedin U. 8. Patent No. 2,147,075, issued to W. J. Zenner on February 14,1939. Such printer is by way of example only, as signals for operatingpermutation or other types of printers may be generated in a similarmanner. According to the embodiment shown, wherein the printer disclosedin the Zenner patent is contemplated, the pattern of segmentation ofring 18 is such that each interval represented by the numeric I00 isequal to an isochronous code signal interval as shown in Fig. 1 of saidZenner patent.

The signal generator 11 is further provided with two sets of rings suchas the segmented ring 82, solid ring 83, and segmented ring 84 traversedby the brushes 86 and the segmented ring 81, the solid ring 88 and thesegmented ring 89 traversed by the brushes 9|. The segmented ring 82 issegmented in such a manner as to transmit telegraph signals indicativeof the thousands and hundreds components of the telephone number, suchas 6 and 2 in the instant example. Likewise, the segmented ring 81 issegmented in such a manner as to transmit the tens and units componentsof the number, such as 00 in the instant example.

It will be understood that it is necessary to provide one-hundred eachof the rings 82 and 81 in order that complete numbers from 00 to 99 maybe transmitted in accordance with each telephone subscriber. However, inview of the fact that it would be mere repetition to include such amultiplicity of distributors in the instant drawings and would serve nouseful purpose, one only of each of such rings have been illustrated.Only one station call letter distributor 18 need be included.

The generated signals, caused by the brushes traversing their respectiverings, originate with an alternating current generator 92 and pass overa common conductor 93 to a conductor 94 leading to the segmented ring18, a conductor 96 leading to the segmented ring 82, and a conductor 9'!leading to the segmented ring 81.

The segmented ring 18 is provided with a start segment 98 which must beof a length appreciably longer than the time required for a completemonopulse signal to be transmitted, insulated segments 99 and signallingsegments l0! which are indicatlvedn monopulsecod'e; of thel'etters- BUG;as previously mentioned. The codese ments: Iill are insulated. from eachotherand from the-start: segment 98 bymeans of the insulated. segments"99. The brushes 81-, 86, and iii are continuouslytraversing;theirassociated rings and. thus a circuit may betracedflfromalternating current generator Q2", over the" common conductor 93,overthe conductor 94,.throughthe start segment 98; over brush 81' asittraverses thestart segment; through the solid distributor ring 19 andover a conductor 192.; from conductor m2 may be traced" through sequenceswitch cam I93 which forms" a closed path upon. the completion of thetelephone circuit, over a conductor. its having; a condenser therein,through an armature IE6 associated with a relay Ill? but which is, inits unoperated or leftward. position, and over a conductor N38 to theconductor 2% previously described, which forms part of the ring circuit.As the brush 8! further traverses the segmented ring I8 it will passover the code segments NH and cause signals to be impressed on theconductor 24, over the circuit just. described.

As previously mentioned, the segmented ring 82 was providedwith codesegments indicative of the thousands and hundreds components of thecalling subscribers number. which are indicated by the. numeral. I99 andv which are separated by meansof. insulation I II.

Alsov as previously described, segmented ring 87 generates signals.indicative of the tens and units. components, such segments beingindicated by the numeral I I2 and separated by the. insulation I53.

It should be noted that the s-egmentson thedistributor rings EB, 82',and 81. are so positioned that none of them occur at thesame time. Thus,as the. brushes GI, 35, and 9E traverse their respective rings, the,start signal wouldbe transmitted first, then the station call. letters.(BUC), and flnally the call numbers (620(1) in such. a manner thatthey would fall in their. normal order.

At the-same time that the circuit is completed between the tWo stationsand the, bell ringing,

occurs, a relay H4 is energized in. accordance with standard telephonepractice. Upon the. energization of, the relay II lits armatures I It,

Ill, and III are. attracted. thereto, armatures lit and H8 serving to.disconnect theline relay lit from the. calling circuit, in .a, manner.well known in telephonepractice. The attraction of armature Iii will.cause it to engage, its. associated electrical contact i2I.

It might be noted that. the, relay us is comprised of three windings,the. center Winding causing the energization of therelay and theattraction of. the armatures, whereas. the purpose of the right-handandleft-hand windings will become. apparent during the. followingdescription.

The attraction of thearmature I l'Ijin engagement with the contact I2'I.closes electrical circuitsfor. the transmission. of. the numerals ofthe.

calling subscribers station in a manner which will now be described.

As the. brush 86 traverses thev segmented ring 82 and, particularly thecode segments I 85-], an electrical circuit is completed. which may betraced from the alternating current generator 9:2, over the commonconductor 93", 0ver. the con.- ductor st to the segments I09,over thetraversing brush (it, through the solid distributor ring 33, over. a.cable or trunk. IZiZthrough resistor I23, through the winding of theright-hand coil of the The further" circuit relay M4; overaconductor I24to contactpoint':

I E i, through the armature I I I attracted thereto;- through a resistorand l over acabl'e 01" trunk. I265 through the solidring 88, oven thetraversing brush 9i, through the uninsul'ated segment-Riot the segmentedring 89',- and over" a: conductor I 28 to ground 5251 As may be-seenbyreferencete the segmented ring 89'- the uninsulated portionI-2'-'I-thereof is-inalignment'with the section ofthe segmented ring 82assigned to thethousands and hundreds components of" thecallingsubscriber-s number, inasmuch as all the brushesrotate-together;

It should be'noted' that then-rwillbe'on'e hundred leads 9%, onefor-ea'chpair of digits OO-to 99; t'orepresent thousandsand hundreds. Itis also tobe noted that-there will be one-hundred 'leads H25 which-carrysignals similar'to those'on leads t6 except that they represent tens andunits: Apparatus is so provided that the-signals will be generated inproper time relation to-eachother, so that while'the thousands andhundreds signals: are generated thelea'ds I 2 6 Wi11' be-grounded, andvice versa. 33'' this arrangement the two'-- hundred leads servegto-giveseparate-number in dications to ten thousand difierent' numberedtelephoneilinesz.

As the brushes further traverse theirrespective rings a circuit may betraced from alternating current generator-92, over the commonconduct'or9.3, over the conductor'9'i; through'the code-seg-- ments H2 01"". thesegmented ring 87, over the traversing brush" 91-, over the solid ring88; overthe cable or trunk; E25 and the resistortherein, irough thearmature- I-I-T- in engagement with contact I2 l, over the conductorI24, through the right hand" winding of the relay I Hi; through-theresistor I23, overthecabieontrunk I22; through the solid ring 33',overt-he traversing brush 86,

through the uninsulatedisegment I3I= ofthe segmented distributorring8.4, and over a conductor 82 to ground I29. In. the present instance theuninsulated portion- I'BI of the segmented ring as. isaligned with theportion of the segmented ring 8? assigned to the tens and unitscomponents of the calling subscribers number.

The right-hand andleft-handwindings ofthe: relay II l. are. soconstructed. that energization of the right-hand" winding; dueto' thecode segments being traversed as: just. described, will cause a.similarenergization orialt'ernating cur rent to be induced in. the;left-hand winding thereof. As a resultof'such. occurrence the induced'signals in. the, left-hand winding are transmitted over. conductor.I'SS-Iea'ding;fromthe'lefthand coil to the sleeve terminal I,34, over aconductor hill, through thesequenceswitch. cam: I03 forming. a closedpath; over: the conductor" I65, through the armature I06, over theconductor see, and. willthus beireimpressed on the telephone circuit. onthe conductor. 24 of. the tip circuit.

Thereforeas the brushes 81,, 86,,and' SI traverse theirassociatedsegment's;which occurs continuously, alternating currentsignals will be 1mpressed' on. the conductor 24. in a manner as has.just been described for both call letters and numerals indicative of.the calling, subscriber's station. However, even thoughthisoccursduring. the time that the" bell; ringing. mechanism is operatingthe.added superimposed alternating, current willnotiaffect'the.standarditelephone circuit in any way.

It might be. noted at this;t1me. that. in. the. event that'acalled'subscriber answeredhis phone a relay I35 would energize accordingto standard telephone practice resulting in its armature I36 beingattracted thereto and thus completing a circuit which may be traced fromground, through the armature I36 which is now in its attracted orright-hand position, over a conductor I31 to junction point I38, over aconductor I39, and through the winding of the relay I91 to groundedbattery MI. The resultant energization of the relay I81, causing itsarmature I96 to be attracted thereto, would break the circuit previouslytraced from the conductors I92 and I49 and preclude further signals (BUC6200) from being transmitted to the conductor 24. Therefore, under thiscondition no further signals indicative of the calling subscribersstation would be transmitted to or be placed on the telephone circuit,thus allowing conversation to occur in its normal uninterrupted manner.

As was previously mentioned, the bell ringing mechanism causes the relay16 to operate, thus causing it to be energized and de-energizedsuccessively in accordance with the necessary rings of the bell. As aresult of the energization of the relay 16 it will cause its associatedarmature I42 to be attracted thereto which results in an electricalcircuit being established which may be traced from grounded battery I43,through the armature I42 to a contact point I44 with which it is now inengagement, over a conductor I46 and through the winding of a magnetI41, over a conductor I48 to junction point I49, over a conductor II,through a sequence switch cam I52 which now forms a closed pathcondition, over a conductor I53 and through an armature I54 of relay 68,previously mentioned, to ground. As was also previously mentioned,inasmuch as the telephone circuit which was fully traced is not actuallyestablished until such time as the receiver is removed at the calledstation B, the relay 68 which forms part of the telephone path will notbe energized and thus its armature I54 will be in an unoperatedcondition so as to allow the establishment of the circuit just traced.The magnet I41 will be energized and de-energized intermittently inaccordance with a similar condition of the ringing relay 16.

The armature of the magnet I41 is formed of a lever I56 pivoted at I51and normally urged in a clockwise direction by means of a spring I58.The lever I56 has pivotally connected thereto at I59 a pawl I6I which isnormally urged in a counterclockwise direction by means of a spring I62toward engagement with an associated ratchet I63. Counterclockwisemotion of the pawl I6I is limited by means of a stop I64. The ratchetI63 is provided with a stop arm I66 associated therewith which islimited in its clockwise movement under urging of a coiled spring (notshown) by means of a stop I61 to return the ratchet I63 to itsunoperated position.

Also associated with the ratchet I 63 is a detent I68 which is pivotallymounted and which has an extended portion I69 which forms the armatureof a magnet I1I. The detent I68 is normally urged in a clockwisedirection away from the ratchet I63 by means of a spring I12. However,during the time that the relay 68 is de-energized and the sequenceswitch cam I52 completes its circuit, an electrical circuit may betraced from ground, through the armature I54, through the conductor I53,through the sequence switch cam I52, over the conductor I5I' to junctionpoint I49, over a conductor I13, and

8 through the winding of the magnet "I to grounded battery I14. Themagnet I1I will thus become energized attracting its armature I69thereto which results in the detent I68 being engaged in the teeth onthe periphery of the ratchet I63 thereby preventing the ratchet frommoving in a clockwise direction.

Each time that the armature I42 is attracted by the energization of theringing relay 16, it engages contact I44 which results in theenergization of the magnet I41. At such time the armature lever I56 willbe attracted thereto, the pawl I6I will be moved upwardly in engagementwith a tooth of the ratchet I63 and the ratchet will be turned in acounterclockwise direction a distance equal to the distance betweensuccessive teeth. The ratchet thus will be turned one tooths distanceeach time the telephone bell rings at the called subscribers station B.

As the ratchet I63 moves in a counterclockwise direction a predetermineddistance, its stop arm I66 moving therewith will engage a movableswinger I16 causing it to pivot in a clockwise direction and engage itsassociated contact I11. At such occurrence, an electrical circuit isestablished which may be traced from grounded battery I18, through thecontact I11, through the movable swinger I16, over a conductor I19,through a contact I8 I through a movable swinger forming part of acommon member I82 which is in engagement therewith at this time, over aconductor I83 tojunction point I 84, over a conductor I 86 and throughthe winding of a relay I81 to ground. As a result of the completion ofsuch electrical circuit the relay I81 will be energized and will remainin this condition inasmuch as the detent I66 will cause the electricalswing I16 to remain in contact with its associated contact point I11through its action on the rachet I63 until such time as the magnet I1Imay become de-energized. Such magnet however does not becomede-energized until such time as either the relay 68 becomes energized orthe sequence switch cam I52 opens a circuit, which will not occur untilthe called subscriber removes his receiver from the hook or the callingsubscriber abandons the phone call, respectively.

Upon energization of the relay I81 and the resultant attraction of itsarmatures I88 and !89 thereto, two electrical circuits are established,which will now be traced. One such electrical circuit may be traced fromground, over a conductor I9I, through the armature I88, over a conductorI92, and through the winding of a magnet I93 to grounded battery I94.The resultant energization of the magnet I93 causes its armature I96which is piovtally mounted at I91 and normally urged in a clockwisedirection by means of a spring I98 to be moved in a counterclockwisedirection thereby causing its detent arm I99 to engage the teeth of anassociated ratchet 29I which is securely mounted to a shaft 292. Theshaft 292 has a stop arm 293 securely fastened thereto which limits theclockwise movement of the shaft and ratchet by engagement with a stop294 toward which it is biased by means of a coil spring, not shown.

The second electrical circuit which is established upon the energizationof the relay I81 may be traced similarly to that with respect to theenergizing circuit for the relay I81 up to the conductor I86, thence tocontact 296, through the armature I89 in engagement therewith, over aconductor 291 to junction point 298, over a conductor 299 to an armature2| I of a relay 2 I 2 which isat this time in a de-energized condition,through a contact 213, over conductor 214, and through the winding ofthe relay 2 [2 to ground. As it was just mentioned that the circuit justestablished was traced through the armature 2i i and depended on itsbeing in its unattracted condition due to the de-energization of therelay 252, the energization of the relay 212 will cause such circuit tobe broken momentarily, thus once again causing de-energization of therelay H2. The relay 2E2 acts as a stepping relay for a sequence switchor finder which comprises six contact rings M6 to RI, inclusive. Thesequence switch or finder is providedso that one contact point on eachof the rings 211 and 2 i8 will be associated with the instant incomingselector circuit 14 and cause the alternating signals generated thereinto be passed to an amplifier 223 in a manner and for a purpose whichwill be described hereinafter.

At such time as the stepping relay 212 advances the contact arms of theselector switch to a position whereby they engage the contact points associated with the instant example, which as may be seen on Fig. 3 is thethird contact point, the circuit previously traced for the energizationof the relay I81 over the conductor I83 to junction point I84 may befurther traced over a conductor 224 to the third contact point of theselector ring 2H5, over the movable contact arm in engagement therewith,over a conductor 226 and through the right-hand winding of a relay 221to ground. Upon the energization of the right-hand Winding of the relay221, the associated armature 228 will be attracted thereto placing it inengagement with contact 22s and extending the circuit from the conductor226 through the contact 229, over the armature 228, over a conductor23!, through the left-hand Winding of the relay 221, over a conductor232, over the conductor 214, and through the winding of the steppingrelay 2I2 to ground. Such acts as a locking circuit for the relay H2 andthus prevents the stepping switch from operating to move the movablearms past the No. 3 contact point of the contact rings 216 to 22l,inclusive.

The relay 221 remains energized over its energizing circuit which wastraced through the third contact point of the contact ring 215 andattracts its armatures 233 and 234 thereto, placing them in engagementwith their associated contact points.

Due to the attraction of armature 233 a circuit is established which maybe traced from the line 38 in the incoming selector circuit 14, over aconductor 236, through the third contact point of the contact ring 2l1,over the movable arm in engagement therewith, over a conductor 231,through the armature 233 and to the amplifier 223. Due to the attractionof the armature 234 a circuit may be traced from line 49 of the incomingselector circuit 14, over a conductor 2% to the third contact point ofthe contact ring 253, through the movable arm in engagement therewith,over a conductor 239, and through the armature 234 to the amplifier 223.

The amplifier 223 serves not only to amplify the alternating currentsignals transmitted from the v signaling generator 11 but also toconvert them from alternating current to direct current sigrials.

If the above circuit connections occur at the time of the transmissionof any signal from the signal generator 11 other than that of the startsignal es, it will have no immediate efiect on the apparatus hereinafterto be described. Thus,

in the following description it should be assumed that the circuitspreviously traced have been set up and that the brush 8| is traversingthe start segment 98 and sending an alternating carrier currentindicative thereof to the amplifier 223, which is thereat converted todirect current.

The reception and conversion to the direct'current signal of the startimpulse results in the establishment of a circuit which may be tracedfrom the amplifier 223, over a conductor 24!, through the winding of afast operating relay 242, through the winding of a slow operating relay243 and over a conductor 244 back to the amplifier 223. The reasonpreviously stated that no effect would result from the transmission ofany other than the start signal at this time is due to the fact that theslow to operate relay 243 is responsive only to the start signal ofevery one of the transmitted signals and will not energize upon thereception of any other signals. Upon the reception of the start signaland the energization of the relays 242 and 243 their armatures 241 and246, respectively, will be attracted thereto. Due to the energization ofthe relay 243 and the attraction of a second armature 248, an electricalcircuit is established which may be traced from ground, through thearmature 248, over a conductor 249, and through the winding of a relay25l to grounded battery 252.

The resulting energization of the relay 25| causes its armature 253 tobe attracted thereto resulting in the establishment of an electricalcircuit from ground, over a conductor 254, through the attractedarmature 253, over a conductor 256, and through the winding of a magnet251 to grounded battery 258. The magnet 251 upon energizing attracts itsarmature 259, which is normally held away therefrom by means of 'aspring 26!, causing it to pivot about its pivot point 262 and cause itsdetent portion 263 to engage a tooth in the ratchet wheel 21",previously described, thereby causing the ratchet wheel to be stepped adistance equal to the distance between successive teeth in acounterclockwise direction. Aswas also previously mentioned, the detentI99 is in engagement with the teeth of the ratchet wheel 20! thusprecluding the ratchet from moving back to its original position afterthe magnet 251 becomes de-energized.

The movement of the ratchet 201 causes its shaft 202 to move a similardistance resulting in a cam 264 which is securely fastened to the shaft232 to move a similar distance. Such movement of the cam 264 causes thehigh portion of the periphery thereof to engage a movable swinger 266and move it in a clockwise direction in engagement with an associatedcontact 261. Upon the closure of the contact pair formed by the swinger266 and the contact point 261, an electrical circuit is establishedwhich may be traced from ground, through the contact point 261, over theswinger 266. over a conductor 268, through contact point 269, over amovable swinger formed as part of the common member I82, over aconductor 21!, and through the winding of a relay 212 to groundedbattery 213.

The energization of the relay 212 causes its associated armatures 214,216. and 211 to be attracted thereto resulting in the establishment ofcertain circuits.

One of the just mentioned circuits may be traced from ground, throughthe armature 214, over a conductor 218, through the movable arm andthird contact point of the contact ring 2l9, over a conductor 219 andthrough the winding of to the alternating current source 282.

relay 62 (Fig. 2) to grounded battery 28l. The

. 63 through armature 6|, and from conductor 1| to conductor 13, througharmature 12. Such formed part of the telephone circuit.

The attraction of the armatures 216 and 211 results in the establishmentof an electrical circuit which may be traced from alternating currentgenerator 282, through a conductor 283, over the armature 216, over aconductor 284, through the right-hand winding of a transformer 286, overa conductor 281, through the lefthand winding of a transformer 288, overa conductor 289, through the armature 211 and back As a result of thecircuit just traced alternating current will be induced in theright-hand winding of the transformer 288, will pass over the conductor29l, through the movable arm and third contact point of the selectorcontact ring 220, over a conductor 292, through the armature 12, overthe conductor 13, through the connector 14, over the lowermost of thetwo lines |1 shown in the final selector I6, over a conductor 293,through a contact pair 294 at the called subscribers station B, over aconductor 296, through the right-hand winding of a printer magnet -291,through a condenser 298, and through an alternating current motor 299utilized for driving the receiving monopulse printer.

The alternating current induced in the lefthand winding of thetransformer 286 may be a conductor 306, through the left-hand winding ofthe relay 291, and through the condenser 298 to the motor 299. Inasmuchas the alternating current passes through the two windings of the magnet291 in reverse directions no magnetic effect is produced but there isadded a slight resistance to the current flowing to the motor 299. Suchslight resistance merely diminishes slightly the alternating currentsupplied to the motor 299 but will not affect its operation due to thealternating current being supplied. However, direct current passesthrough the two windings in such a manner so that the magnetic effectsare added, causing the magnet 291 to respond to the direct current. Itshould be further noted that even though the direct current isinterrupted during signalling the alternating current is interrupted inone coil only and the motor 299 will continue to operate. A similaroperation may be seen by reference to U. S. Patent No. 2,237,951, issuedto L. M. Potts on April 8, 1941.

The reason for applying alternating current to the motor 299 at thistime is to allow it to start into operation and come to an operatingspeed prior to the time that the printer is operated to record the codesignals transmitted thereto.

While the transformers 286 and 288 have been shown as separatetransformers such has been done for facility of illustration andactually the primaries are wound on a single magnetic core and thesecondaries are also wound on the same magnetic core. The twosecondaries are wound in such a manner that they both deliver the samephase alternating current. However, when direct current passes throughthe two series connected windings they cancel each other and produce nomagnetic effect, but merely act as resistors.

At the time of energization of the relay 62, an electrical circuit isestablished which may be traced from grounded battery 391 (Fig. 3), overa conductor 308, through a contact pair 309 which is closed at thistime, over a conductor 3| I, through the right-hand winding of thetransformer 288, over the conductor 29| and swinger arm to the No. 3contact point of the contact ring 220, over the conductor 292, throughthe armature 12 in engagement therewith, over conductor 13, through theconnector 14 leading to the lowermost of the two lines H in the finalselector l6, over the conductor 293, through the contact pair 294, overthe conductor 296, through the right-hand winding of the printer magnet291, over a joining conductor 3|2, through the left-hand winding of theprinter magnet 291, over the conductor 306, through the contact pair 394(now closed), over the conductor 303 to the uppermost of the two lines|1, through the connector 64 leading to the incoming selector circuit|4, over the conductor 63, through the armature 6|, over the conductor302, through the third contact point and swinger arm in engagementtherewith of the contact ring 22 I, over the conductor SM and throughthe left-hand winding of the transformer 286 to ground. The directcurrent just traced causes the printer magnet to remain energized andprecludes the operation of the printer until such time as a signal isreceived which releases the printer for operation in accordance with thedescription in the aboveidentified Zenner patent. The direct current sogenerated has no effect on the driving motor 299 inasmuch as because ofthe condenser 298 it does not pass to such motor; the condenser 298passes alternating current only.

Upon the energization of the slow operating relay 243 and fast operatingrelay 242, and subsequent attraction of the armatures 246 and 241,respectively, an electrical circuit is established which may be tracedfrom ground, over a conductor 3| 3, through the armature 246, over aconductor 3|4, through the armature 241, over a conductor 3|6, andthrough the winding of a relay 3|1 to grounded battery 3|8. Theenergization of the relay 3|1 causes its armature 3|9 to be attractedthereto resulting in engagement with the contact point 32| and thebreaking of the contact pair 322. However, the energization and theresultant attraction of the armature has no effect at this time.

As the signal generator 11 (Fig. 1) completes the transmission of thestart signal and the brush 8| passes to the first insulated portion 99of the segmented ring 18, a signal will no longer be incoming to theamplifier 223 which results in the de-energization of the fast operatingrelay 242 and the slow operating relay 243. Immediately, due to thedropping off of the armature 248, the relay 25| will de-energize causingits armature 253 to also fall away therefrom, in turn resulting in thede-energization of the stepping magnet 251. The magnet 251 no longerattracts its armature 259 thereby allowing the pawl 263 to return to itsnormally unoperated condition away from the ratchet 20|. Due to theoperation of the detent I99 prior to this time,

through the relay 3H will not de-energize during this short transfer ofground circuits still there is no effect on the remaining circuits dueto its de-energization.

As the brush 8| traverses further the segmented ring 18 causing thesignal pulses llll to be transmitted over the line and to the amplifier223, such signals will result in the fast operating relay 2%2 becomingenergized but will have no effect on the slow to operate relay 243which, as

previously mentioned, becomes energized only upon the receipt of thestart signal due to its duration.

The energization of the fast operating relay 2 33 causes its armature241 to be attracted thereto resulting in ground previously tracedthrough contact 323 no longer being supplied to the circuit for theoperation of relay 3H and inasmuch as relay 243 is not energized withits armature 2A6 attracted thereto, no ground will at this time besupplied for the relay circuit.

However, even though the relay 3|! becomes deenergized and its armature3l9 falls away therefrom allowing the contact pair 322 to once againclose, still there will be no effect on the remainder of the circuit atthis time.

The receipt by the amplifier 223 of the signals generated as the brush86 traverses the segmented ring 82 and as the brush 9| traverses thesegmented ring Bl will have no effect on the signaling circuit otherthan that just described upon I the receipt of the signals fromsegmented ring #8.

It is to be remembered that mention was made that the brushes 8 l, 86,and SH continuously operate to traverse their respective rings.Therefore,

after the cycle is completed, which was described immediately above, thebrush 8! will once again traverse the start segment 98 of the segmentedring '53 resulting in the long duration start si nal being transmittedover the line and received by the amplifier 223. Upon the receipt andconversion to direct current of such signal the fast operating relay 232 and the slow to operate relay 2% will once again be energized overthe circuit which was pr viously fully described. As a result of theenergization of the relay 2% its armature 248 is attracted thereto onceagain establishing the electrical circuit for the energization of therelay 25! which thereupon causes its armature 253 to be attractedthereto. The attraction of the armature 253 once again establishes thecircuit for the energization of the magnet 251 causing its armature 253to be attracted thereto and the pawl 263 to once again engage theratchet Wheel 2t! and turn it in a counterclockwise direction a distanceequal to the distance between successive teeth, in which position it isheld by the detent E99 which is still in engagement with the teeth ofthe ratchet. Upon such movement of the ratchet 29! its shaft 202, towhich it is securely fastened, likewise turns a similar amount therebycausing the cam 26 to likewise move in a counterclockwise directioncausing its high portion to engage a movable swinger 324 and cause it toengage the associated contact 326.

Upon relays 242 and 243 becoming energized 'pair 3535.

and attracting their armatures 24? and 246, re-- spectively, a circuitis once again established for placing ground in the circuit of the relay3]? thereby allowing such relay to energize and attract its armature tiethereto. Such attraction results in the contact 32I being closed and thecontact pair 3222 becoming opened.

Upon the counterclockwise stepping oi the cam 25$ and the resultantmovement of the swinger 324 into engagement with the contact 32%, anelectrical circuit is established which may be traced from ground, overthe swinger 324, through the contact 325, through a contact 32?,

through a movable swinger forming part of the common member 582, over aconductor 32B, and

through the winding of a relay 325'? to grounded battery 33%. Theenergization of the relay 329 causes its armature 332 to be attractedthereto placing it in engagement with its associated contact 333 andcausing the opening of the contact The result of such occurrence is thatbattery 3%? no longer will be supplied over conductor ellt and throughcontact pair 339 for supplying direct current to the printer magnet 2%but instead grounded battery 36? will be supplied through armaturecontact 32!, over a con- 'ductor 335., through armature 332, throughcontact 333, and over the line ill, as previously described, therebycausing the printer magnet 29'? to remain energized.

As the brush of the signal generator '5! passes from the start segmentas to the insulated segment 99, the fast operating relay 242 and theslow operating reiay 2&3 will once again become de-energized, therebyresulting in the armatures 2M and t lt, respectively, no longer beingheld attracted and falling away therefrom. The only effect, with respectto the signal cir cuit is that ground for the energization of the relaySH no longer may be traced through both of the armatures 2s? and 2% butinstead will now be traced through the contact 323 and the armature 241.At this time also the armature 2&8 will no longer be attracted resultingin the breaking of the circuit for the energization of the relay '25!which causes its armature 25% to also fall away. This in turn results inthe circuit for the energization of the stepping magnet 25'? beingbroken with the pawl 233 returning to its normal position out ofengagement with the teeth of the ratchet 29!. However, because detent weremains in engagement with the teeth of the ratchet, the ratchet willremain in stepped position.

As the brush 8! of the signal generator ll? passes to the first signalsegment 53% of the segmented ring it which is indicative of the firstcalling station letter (B) such will be transmitted to the amplifier223, whereat it is converted to 'direct current, resulting in the fastoperating of any signal other than the start relay 25? becomingenergized. Inasmuch. as, as

was previously stated, the slow operating relay 243 does not becomeenergized upon the receipt signal, it will not become energized at thistime. The resultant attraction of the armature 2 1 1? of the will removeground supplied for relay 3H, over omiductor 313 and through contact 323and as 15 battery 301 from supplying direct current to the printermagnet 291 inasmuch as contacts 32| and 309 are both open at this time,thus allowing the printer to start operating in accordance wiith thesignal interval, in a manner described fully in the Zenner patent.

Upon the brush 8| passing from the segment indicative of the letter B tothe subsequent insulated segment 99, no signal impulse will be receivedby the amplifier 223 and the relay 242 will become de-energized. Suchresults in the armature 241 falling away and ground once again beingsupplied over conductor SIB and through contact 323 and armature 241 forthe circuit of relay 3| 1 thereby causing that relay to energize. Uponsuch occurring the armature 3|9 becomes attracted, engages its contact32I, and battery 301 is once again supplied over the previously tracedcircuit thereby resulting in the energization of the printer magnet 291.Such results in the letter B being recorded by the monopulse printer.

The apparatus will thereafter function in a similiar manner in orderthat the letters U0 and the numerals 6200 may be transmitted andrecorded by the printer at the called subscribers station B. It shouldbe remembered that during all this time, that is, as the brush 8|completes its passage over its signal segments and as the br-ush es 86and 9| traverse their signal segments all of which will be recorded inaccordance with the monopulse code at the receiving printer, that theslow to operate relay 243 will not become energized.

After the brushes have made a complete cycle or traversal of theirassociated rings, the brush 8| will once again traverse the startsegment 98 causing the start signal to be transmitted over the line tothe amplifier 223 wherein it will be converted to direct current. Suchsignal causes the fast operating relay 242 to become energized and alsocauses slow to operate relay 243 to become energized, causing thearmatures 241, 246, and 248 to be attracted.

The attraction of armature 248 results in a circuit once again beingestablished for the energization of the relay 25| attracting itsarmature 253 thereto. The attraction of the armature 253 establishes thecircuit once again for the energization of the stepping magnet 251thereby attracting its armature 259 and causing the pawl 263 to step theratchet 20| another step. Such movement of the ratchet causes the shaft202 to likewise move resulting in the cam 264 being moved a third stepin a counterclockwise direction. The effect of such stepping of the camat this time is to cause its high portion to move member I82 in anupward direction resulting in the movable swingers connected theretobeing moved away from engagement with the contacts I8I, 269, and 321,thereby causing certain circuits to be broken, as will now be described.

The opening of the circuit at contact 321 results in the de-energizationof the relay 329 thereby removing the armature 332 from engagement withthe contact 333 and allowing the contact pair 309 once again to close.The disestablishment of such circuit allows grounded battery 301 to beapplied directly to the printer magnet 291, over the conductor 308,through the contact pair 309, and over a circuit which was previouslydescribed.

The opening of the circuit at contact 269 removes ground which waspreviously supplied for the energization of the relay 212 and therebyresults in the de-energization of such relay causing its armatures 214,216, and 211 to fall away from their associated contacts. As a result ofarmature 214 no longer engaging its associated contact the circuitpreviously traced for the energization of the relay 62 (Fig. 2) nolonger will be established and such relay will become de-energized, itsarmatures 6| and 12 no longer being attracted thereto. The result ofthesev armatures no longer being attracted to their relay serves todisconnect the selector contact rings 220 and 22| from the lines I1leading to the called subscribers station B, thus breaking the circuitpreviously described for the direct current to the printer magnet 291,but instead completes connecting lines I1 in the telephone circuitinitially described,

The relay 212 being de-energized results in the armatures 216 and 211 nolonger being attracted and serves to remove the alternating currentsource 282 from the transformers 286 and 281 as previously explained.Even though such did not occur the alternating current previouslydescribed as being supplied to the printer motor 299 causing it tooperate would no longer perform such function due to the fact that thearmatures 6| and 12, over which the circuit for such alternating currentwas traced, no longer are in a position to connect to the lines I1 insuch a manner as has just been described.

As a result of the circuit being broken at contact |8| the battery whichwas supplied for the relays I81, 2|2, and 221 no longer will be suppliedand these relays will all become de-energized. AS a result of thede-energization of the relay 221, its armatures 233 and 234 will nolonger be attracted and the circuit will be broken for supplying thesignals generated by the signal generator 11 to the amplifier 223.

Upon the de-energization of the relay I81 its armature I88 will nolonger be attracted thereto and because of this will break the circuitwhich had been traced for the energization of the magnet |93. Thede-energization of such magnet will result in its armature I96 no longerbeing attracted thereto and under the influence of the spring I98 beingbiased in a clockwise direction in which position the detent portion I99is no longer in engagement with the teeth of the ratchet wheel 20|.Under this condition the ratchet wheel 20| will return through springpower, which is not shown, in a clockwise direction to an unoperatedposition whereat its stop arm 203 engages the limiting stop 204.

As the ratchet 20| and connected shaft 202 move in a clockwisedirection, the cam 264 will move similarly. Such movement to the cam 264returns it to its normal unoperated position, whereat its high portionwill no longer be presented to the swingers 266 and 324 and the memberI82. The latter elements will thus return to the condition initiallydescribed.

Thus, it may be seen that after a complete signal has been received andrecorded at the called subscribers station B which is indicative of thecalling subscribers number, the apparatus will automatically precludeitself from further operation. Under this condition the bell ringingmechanism will continue to operate until such time as the subscriber atthe calling station A returns his receiver to the hook thereby causingthe telephone apparatus to relinquish all the selecting circuits underthe control of the selector control relay in a manner which is wellknown in the telephone art.

It might be mentioned at this time with respect to the prior descriptionwherein it was stated that after a predetermined number of bell ringsthat the ratchet wheel I63 would be advanced sumciently to cause themovable swinger I16 to engage its associated contact H1, that suchpredetermined number of rings should be picked in order to allow aperson sufficient time to reach his telephone but not to allow too muchtime to elapse. In the event that the latter were true, calledsubscribers may refuse to anwer their telephone until such time as thecalling subscribers number had been recorded at the called subscribersstation and thus if the called subscriber felt like conversing with theparticular person whose number had been recorded he would remove hisreceiver. Under this latter condition too much equipment would benecessary and too much time expended in the use thereof in order for itto be a worth while service.

Referring back to Fig. l and the calling subscribers station A, afterthe calling subscriber has assumed that there is no one at the calledstation and decides to abandon the telephone call, he returns hisreceiver to the hook, which, as previously described, is well known inthe telephone art and which causes the relinquishment of the seizedcircuits. Also, as is well known in the telephone art, this results inthe cut-off relay il i becoming de-energized thereby resulting in thebreaking of the circuits from the si naling generator H to the telegraphcircuits previously transmitting the number 6200. At this time theselector cam I33 will also be positioned in such a manner that nocircuit may be established therethrough and the remaining circuit fromthe signal generator 11 will be disconnected from the telephone lines.Thus, at this time the signal generator Tl no longer will supplyalternating current carrier signals to the telephone lines but insteadwill continue to operate having no effect in the circuits. However, atsuch time as another call is instituted from the calling station A thesignal generator 11' will once again be connected in the line circuitsin a manner which has previously been described.

In the event that it is desired to completely preclude the possibilityof a called subscriber refusing to answer his telephone until such timeas the calling subscribers number has been recorded thereat, apparatushas been provided in a modification of the invention to overcome suchcontingency. Such modification is shown in Fig. 4.

In view of the fact that in main the apparatus of Fig. 4 is similar tothat of Fig. 1 and operates in a similar manner, like reference numeralsare utilized in Fig. 4 wherever possible and will indicate memberssimilar t those shown and described with respect to Fig. 1.

Referring specifically to Fig. 4, an assumption should be made that thecalling subscriber at station A has removed his receiver and has dialedthe number of the desired called subscribers station B. The apparatuswill operate in a manner similar to that previously described in orderto complete a telephone circuit which as previously mentioned was tracedthrough the winding of the relay 23. Upon the energization of the relay33 its armatures 336, 331, and 333 will be attracted thereto.

Due to the attraction of the armature 338 an electrical circuit isestablished which may be traced from ground, through armature 338, overa conductor 33S, and through the winding of the slow to release relay34! to grounded battery phony operation.

The signal generator 11 operates in a manner similar to that describedwith respect to Fig. 1 to generate signals indicative of the callingsubscribers number over the conductors I02 and M3,, through the selectorcam I33, over the conductor we and through the armature I03. The circuitmay then be traced over a conductor 348, through a condenser therein,through the armature 343, over a conductor 349, through armature 331,and over a conductor 35!). However, the circuit for impressing thegenerated signals over the circuit just described to the line 24 at theline finder district [2 will not be completed at this time because inorder for such establishment it must be traced through the armature 331which does not make contact with the conductor 349 due to its being heldin its attracted position by the energization of the relay 23.

The bell ringing mechanism will operate similarly to that previouslydescribed, and the apparatus of Figs. 2 and 3 will also operate similar-1y with the exception that no subscriber's station identifying signalswill be transmitted over the telephone circuit to cause recording at thecalled subscribers station.

At such time as the calling subscriber at station A decides that thecalled subscriber at station B is not present and returns his receiverto the hook, the apparatus will function to cause the de-energization ofthe relay 23. Even though the armature 338 is no longer attracted tosupply ground to the energizing circuit of the relay 34!, this relaywill not immediately de-energize inasmuch as, as was previouslymentioned, it is a slow to release relay.

The armature 331 of the relay 23 will return to its unattracted positionthus allowing the generated signals to pass in a manner similar to thatdescribed with respect to Fig. l to the conductor led, through thearmature I36, over the conductor 348, through the armature 343 which isin its attracted position, over the conductor 349, through the armature331 now in its unattracted position, and over the conductor 350 to theline 24 from whence it will pass over telegraph circuits to theapparatus already described of Fig. 3.

The apparatus disclosed in Figs. 2 and 3 will function in a mannersimilar to that previously described in order that the generated signalswhich are transmitted over the telephone circuit may be recorded at thecalled subscribers station B. The slow to release relay 34! will be sotimed that it will not be de-energized until such time as a completecalling subscribers signal has been recorded. At this time, however, therelay 34I de-energizes thereby allowing its armature 343 to return toits unattracted position thus breaking the circuit which was previouslydescribed as having been established for the conduction of signalsgenerated by the signal generator TI to the line 24 of, the telephonecircuit. Thus at this time the apparatus will once again be in readinessfor the calling subscriber at station A to initiate another telephonecall and to operate at that time.

It might be mentioned at this time that upon the replacing of thereceiver to the hook at the calling subscribers station even thoughrelay 23 becomes de-energized immediately, the remaining circuitconnections between the calling subscribers station A and the calledsubscribers station B will not be relinquished until such time as thecalled subscribers number may be recorder at the called subscribersstation. Such occurs because the relay 341 is energized during thistime, and its armature 344 is attracted thereto thus supplying groundover an obvious circuit through the sequence switch cam 341 for theselector control relay, not shown.

The above apparatus will operate to record a calling subscribers numberat the called subscribers station but has no provisions wherein messagesor other material may be transmitted and recorded at the calledsubscribers station. In view of such, apparatus disclosed in Fig. hasbeen provided which contemplates the use of a leave word operatorsposition for receiving orally a message to be left at the calledsubscribers station, the operator controlling transmission of suchmessage.

Only sufiicient apparatus has been provided in Fig. 5 in order todisclose the operation of this embodiment of the invention. It iscontemplated that the apparatus for causing the bell ringing mechanismto operate and the apparatus operating to translate and record thesignals at the called subscribers station, such as shown in Figs. 2 and3, will be incorporated for use with the present modification as willthe regular panel dial system telephone circuits.

Specifically, referring to Fig. 5, a calling subscribers station hasbeen identified by the numeral 35| which is connected by means of lines352 through a final selector 353 to the instant leave word operatorsstation. It might be noted that while only a final selector has beendisclosed, it is to be understood that a line finder district, incomingselector, and any other necessary selectors may be included even thoughnot shown. The calling subscribers station 35I will be connected to theoperators leave word system through the various selectors including thefinal incoming selector 353 as a result of the calling subscriberdialing some number associated with the leave word operator, such as thenumeral 0,

for instance. As a result of such dialing, a circuit will be establishedwhich may be traced over line 352, over a conductor 354, through anarmature 356, through the left-hand winding of a relay 351, to groundedbattery 358. As a result of the energization of the relay 351 itsarmature 359 will be attracted thereto resulting in the grounded battery358 being applied through the armature 359 and over a conductor 36I tothe grounded illumination source 362, such as a normal light bulb. Theillumination of such light will notify the leave word operator thatsomebody desires to communicate with her and she thereupon will insertthe plug 363 in the jack 364. Such action results in grounded battery366 being supplied through the plug and jack connection, through thewinding of a relay 361 to ground, resulting in the energization of thatrelay and the attraction of its armature 356. Upon the armature 356moving toward the relay it opens the circuit which was previously tracedover conductor 354 and through the armature 356 for causing theillumination of the light 362, thereby resulting in the light beingextinguished.

At the same time, the operator may throw the the associated key contacts369 to be removed from engagement with their inner contacts and placedin engagement with their outer contacts. Such action causes the plug 363to be connected over the plug leads, through the key contacts 369 andtheir outer associated contacts to an operators set which is indicatedgenerally by the numeral 31! and which is of the type in general use atthe present time. The leave word operator may thus communicate orally,utilizing the set 31!, with the calling subscriber, thereby beingadvised of the message which the calling subscriber wishes delivered tothe called subscriber.

After the operator has been advised as to the desired message the plug363 will be removed from engagement with the jack 364 and inserted inthe jack indicated generally by the numeral 312 instead. The key 368Will be withdrawn from engagement with its contacts 369 and insteadplaced in a position to engage its associated contacts 313 in such amanner as to place them in engagement with their outer contact pointsinstead of their inner contact points. The result of such action is toestablish a circuit including the dial unit 314, through the outercontacts associated with the key contacts 313, through these keycontacts, over the conductors 316, through the key contacts 369 to theplug 363, thence to the jack 312 and over the telephone circuit. Theoperator thence will operate the dial 314 dialing the proper number forthe called subscribers station which will operate through line finderdistrict indicated generally by the numeral 311, through the regulartelephone sequence switches which are not shown, and eventually overlines 318 to the called subscribers station 319-. The effect of thiswill be to complete a telephone circuit between the leave wordoperator's station and the called subscribers station.

After such circuit has been established and the standard telephone bellringing mechanism has operated in a manner well known in the art and asindicated previously, the apparatus disclosed in Figs. 2 and 3 willoperate in a manner as described with respect to the principalembodiment of the invention. Thereafter the operator will remove the key368 from engagement with its associated key contacts 313 allowing suchkey contacts to engage their inner contact points resulting in the dialunit 314 being disconnected from the circuit. Simultaneously a key willbe operated to cause the key contacts 38I to engage l their associatedcontact points resulting in an alternating current generator 382 beingconnected over the conductors 383 to the primary of the transformer 384which induces current in the secondary windings of the transformer 384which current passes over the conductors 386 to the contact pointsassociated with the key contacts 38E and thence over previously tracedcircuits including key contacts 313, the conductors 316, the keycontacts 369, the plug 363 and the jack 312. However, the alternatingcurrent from the source just described does not normally pass over thedescribed circuits because of a shunt circuit between the conductors 386which includes a conductor 381, a manually operable key contact pair388, a contact pair 389 and a conductor 39!. Thus, during a normalcondition at which time the key contact pair 388 is closed as is thecontact pair 389, a shunt will exist on the line whereby no alternatingcurrent will be transmitted thereover.

The normally closed contact pair 389 is within a monopulse transmitter392 which is of the type disclosed and described in U. S. Patent2,173,147 issued to W. J. Zenner on September 19, 1939. Such patentdiscloses a similar contact which is likewise normally closed.

In order for the apparatus to be put into operation the operator mustopen the key contact pair 383 twice in succession, each time of a fairlylong duration in order that the shunt may be removed from the line andalternating current impulses may be transmitted thereover which willcause the operation of the apparatus shown in Fig. 3 and particularlythe double stepping of the ratchet 26! to advance the cam 264 to aposition whereat the movable swingers 266 and 32s engage theirassociated contacts Zlil and 526, respectively. As has been fullydescribed hereinbefore, such results in the monopulse receiver at thecalled subscribers station being conditioned in readiness for thereceipt of monopulse signals and the recording of the proper message inresponse thereto.

Thereafter, the key 388 will be again closed resulting in the shunt onceagain being supplied to the circuit, thereby terminating thetransmission of alternating current thereover. However, the leave wordoperator will now operate the monopulse transmitter 392 in a mannerfully described in th just previously mentioned Zenner patent resultingin the contact pair 339 being opened in accordance with monopulsesignals for the characters of the message to be transmitted which hasthe effect of once again removing the shunt from the circuit andallowing the alternating current to pass thereover in accordance withthe monopulse signals. Such current will be received in the amplifierand cause the operation after conversion to direct current of the relaysand apparatus as disclosed and in a manner described with respect to theprincipal embodiment.

It should be remembered that though alternating current has beendescribed as passing over the line, direct current will still beutilized for the telephone circuit connection as is normally done in thetelephone field.

After the leave word operator has transmitted the entire message bymeans of operating the monopulse transmitter 382, the plug 363 may beremoved from the jack 372 thereby resulting in the telephone circuitsbecoming disestablished and returning to their original unselectedconditions. Oi course, the key .388 may also be operated to send a longpulse, which will cause operation similar to that of the initialdescription.

While a single leave word operators unit has been shown and described itshould be noted that there may be several in each exchang which may alsohave several operators and apparatus for their use which would include aplurality of jacks 35d and lights 362 in order that more than one callcould be handled at a single time at the leave word operators station.

t is obvious that both the initially described apparatus and the leaveword operators apparatus may be utilized in the same system. Thus, thelatter apparatus would only be utilized when it is desired to leave .amessage other than the mere calling subscribers designation,

It should also be noted that the manual operable key 388 which has beenprovided for the transmission of two long impulses may be substituted,by a button operated commutator or by any other means which will servethe purpose.

iii

Even though specific embodiments of the invention have been described it.is fundamental that such invention is not limited to the specificdisclosures shown, but instead includes any modifications or alterationswhich incorporate the spirit of the invention.

W hat is claimed is:

l. in combination with a telephone circuit including a central station,a calling subscribers station, a called subscrib'ers station, and bellringing mechanism, of means at said central station to generaterepeatedly a group of signals indicative of the calling subscribersstation, means to impress the repeated group of generated signals onsaid telephone circuit when said circuit is in a ringing position, atelegraph recorder at said called subscribers station, means tocondition said telegraph recorder for operation, means to cause one onlyof said repeated group of generated signals indicative of said callingsubscribers station to be recorded by said telegraph recorder, and meansto cause said conditioning means to operate after a predetermined periodof operation of said bell ringing mechanism.

2. In combination with a telephone circuit in cluding a central station,a calling subscribers station, a called subscribers station, and 'bellringing mechanism, of means at said central station to generaterepeatedly a group of signals indicative oi the calling subscribersstation, :means to impress the repeated group of generated signals onsaid telephone circuit when said circuit is in a ringing position, atelegraph recorder at said called subscribers station, means tocondition said telegraph recorder for operation, means to cause a groupof generated signals indicative of said calling subscribers station tobe recorded by said telegraph recorder, means to preclude the recordingof more than a single group of said repeatedly generated group ofsignals indicative of said calling subscribers station, and means tocause said conditioning means to operate after a predetermined period ofoperation of said bell ringing mechanism.

3. In a communication system, a telephone circuit including a centralstation, a calling subscribers station, :a called subscribers stationand bell ringing mechanism, means under the control of the callingsubscribers station to place said circuit in a ringing position andcause open ation of said bell ringing mechanism, means at said centralstation to generate repeatedly a group of signals indicative of thecalling subcrib-ers station, a telegraph recorder at said calledsubscribers station, means to condition said telegraph recorder foroperation, means to cause said conditioning means to operate after apredetermined period of operation of said bell ringing mechanism, meansoperating after said ringing position is discontinued to cause saidrepeated group of generated signals to be impressed on said circuit, andmeans to cause one only of said repeated group of signals indicative ofsaid calling subscribers station to be recorded on said telegraphrecorder.

4. In a communication system, a telephone circuit including a centralstation, a calling subscribers station, a called subscribers station andbell ringing mechanism, means under the control of the callingsubscribers station to place said circuit in a ringing position, andcause operation of said bell ringing mechanism, means at said centralstation to generate repeatedly a group of signals indicative of thecalling subscribers stdtion, a telegraph recorder at said calledsubscribers station, means to condition said. telegraph recorder foroperation, means to cause said conditioning means to operate after apredetermined period of operation of said bell ringing mechanism, meansoperating after said ringing position is discontinued to cause sadrepeated group of generated signals to be impressed on said circuit,means operating in response to the repeated group of signals indicativeof said calling subscribers station to further condition said telegraphrecorder for operation, and means responsive to a succeeding one of saidrepeated group of signals indicative of the calling subscribers stationto cause the operation of said telegraph recorder.

5. In a communication system, a calling station, a called station, acentral station, bell ringing mechanism, means at said central stationto generate repeatedly a group of signals indicative of the callingstation, means to connect said calling station and said called stationthrough said central station for communication, a recorder at saidcalled station, means to condition said recorder for operation, means totransmit said repeated group of code signals indicative of said callingstation, means to cause said recorder to respond to one onl of saidrepeatedly transmitted group of signals, and means to cause saidconditioning means to operate after a predetermined period of operationof said bell ringing mechanism.

6. In a combined telephone-telegraph circuit, a calling subscribersstation, a called subscribers station, means to condition a circuitbetween said calling and called subscribers stations, means to generatealternating current signals on said circuit indicative of said callingsubscribers station, a telegraph recorder at said called subscribersstation, means to convert said alternating current signals to directcurrent signals, means responsive to the failure of a talking circuit tobe established and under the control of said direct current signals tocondition said printer for operation, and means to cause said printer torecord signals indicative of said calling subscribers station.

7. In a call recording system, a calling subscribers station, a calledsubscribers station, a central station, bell ringing mechanism, means tocondition a circuit between said calling and called subscribers stationsthrough said central station, means at said central station to generateon said circuit repeatedly a group of signals indicative of said callingsubscribers station, a recorder at said called subscribers station,means to condition said recorder for operation, means to cause saidconditioning means to operate after a predetermined period of operation:of said bell ringing mechanism, means responsive to certain of saidrepeated group of signals to further condition said recorder foroperation, and means to cause the succeeding repeated group of signalsto be recorded by said recorder.

8. In a call recorder system, a calling subscribers station, a calledsubscribers station, a central station, bell ringing mechanism, means tocondition a circuit between said calling and called subscribers stationsthrough said central station, means at said central station to generaterepeatedly a group of signals indicative of said calling subscribersstation, each of said repeated group of signals including an initialstart impulse, a recorder at said called subscribers station, means tocondition said recorder for operation, means to cause said conditioningmeans to operate after a predetermined period of operation of said bellringing mechanism, means under thecontrol of said start impulses tofurther condition said recorder for operation, means under the controlof said start impulses to cause said recorder to record one of saidrepeated group of signals indicative of said calling subscribersstation, and means under the control of said succeeding start impulse topreclude further operation of said recorder.

9. In combination with a telephone circuit including a callingsubscribers station, a called subscribers station, and means toestablish a circuit between said stations including tip, ring, andsleeve connections, of means to generate signals indicative of thecalling subscribers station, means to cause some of said signals to beimpressed on said sleeve connection, means to cause the remaining ofsaid signals to be impressed on said ring connection, and means to causeall of said signals to be transmitted to said called subscribersstation.

10. In a call recording system, a calling subscribers station, a calledsubscribers station, means to transmit a plurality of similar groups ofsignals indicative of said calling subscribers station, means to precedeeach group of signals by a special signal longer than the longest signalin each group, a recorder at said called subscribers station, and meanscontrolled by said special signal to render said recorder responsive toa single group of signals only.

11. In a communication system, a calling station, a called station,switching apparatus, means to extend a circuit between said stationsthrough said switching apparatus, means to generate groups of signalsindicative of said calling subscribers station, means responsive to adisconnect signal from said calling station to impress said groups ofsignals on said circuit, means to .prevent said switching apparatus frombecoming released, and means to record a single group of signals at saidcalled station.

12. In a communication system, a calling station, a called station,switching apparatus, means to extend a circuit between said stationsthrough said switching apparatus, means to generate groups of signalsindicative of said calling subscribers station, means responsive to adisconnect signal from said calling station to impress said groups ofsignals on said circuit, means to prevent said switching apparatus frombecoming released, means to record a single group of signals at saidcalled station, and means to release said switching mechanism todisconnect said circuit after said single group of signals is recorded.

13. In a call recording system, a calling subscribers station, a calledsubscribers station, a central station, bell ringing mechanism, means tocondition a circuit between said calling and called subscribers stationsthrough said central station, means at said central station to generateon said circuit repeatedly a group of signals indicative of said callingsubscribers station, a recorder at said called subscribers station,means to condition said recorder for operation, means to cause saidconditioning means to operate after a predetermined period of operationof said bell ringing mechanism, means responsive to certain of saidrepeated group of signals to further condition said recorder foroperation, means to cause the succeeding repeated group of signals to berecorded by said recorder, and means under the control of the nextsucceeding repeated group of UNITED STATES PATENTS signals to precludefurther openaltion of said rerd Number Name Date MARTHA W. 0. POTTS,1,337,310 Goodrum Apr. 20, 1920 Ewecutria: Under. the Last Will andTestament of 1,793,762 Tilden Feb. 24, 1931 Louis M. Potts, Deceased.,810,865 Warwick June 16, 1931 1,887,588 Elkins Nov. 15, 1932 REFERENCESCITED 2,094,151 Goheorel et a1 Sept. 28, 1937 The following referencesare of record in the i0 file of this patent:

